Article 800

The law presumes that every person is of sound mind, in the absence of proof to the contrary.

The burden of proof that the testator was not of sound mind at the time of making his dispositions is on the person who opposes the probate of the will; but if the testator, one month, or less, before making his will was publicly known to be insane, the person who maintains the validity of the will must prove that the testator made it during a lucid interval. (n)